If you arrest 25 white people and 75 black people in that group than already you can falsely report that black people commit 75% of the crime. Then, when police run the same test again, they'll look back and realize that black people commit 75% of the crime and instead they'll arrest 95 black people and 5 white, find that they're all criminals, and deduce that black people now commit 95% of crime. This is how using misleading and inconclusive data can lead to a whole world of misfortune for us.
Now that there's so many criminals that are coming in, you have a huge shockwave of judicial handicapation that results in low resources and a lot of people being charged with hefty crimes for doing nothing or being innocent. The more arrests you make the less money you spend on each individual case, the more careless it gets, the quicker the trial, the more time someone has to sit in jail for something they didn't even do. Then, the families of the criminals are now missing a family member, feel resentment towards the system and the police especially, and develop subconscious hostility towards the police. As a result, the police begin to fear minorities because they hate them now so they act more defensive during arrests towards minorities, and end up doing stupid stuff or doing too much and killing the suspect for some dumb stuff. Now you have an angrier population of people.
Arresting more people isn't a solution, you have to start from the core of the issue and end the source. Every time you say "well maybe black people should stop being criminals" or "BLM is a terrorist group" you're essentially adding on to the problem even more. You say it, your friends hear it, they say it, other people hear it, it spreads, and soon you have a divide. You separate people instead of bringing them together.